There is known a device for securing a blanket module to a vacuum vessel of a fusion reactor comprising flexible hollow support designed in the form of rods mounted between two flanges, wherein one of the flanges couples the support with the vacuum vessel and the other flange is connected with the blanket module by means of a threaded fastener with a locking sleeve fixed in the blanket module by deformation (Russian Patent No. 2563975, IPC G21Bl/17, published on Sep. 27, 2015).
The known device comprises the threaded fastening member being a screw bolt having a head located in the cavity of the flexible support and a threaded part fixed in a threaded hole of the module. The locking sleeve is made from two separate elements rigidly interconnected along a tapered surface. One of the said elements is made in a form of a rod with a head matching with the hole in the end face of the screw bolt threaded portion, wherein the end portion of this element is tapering. The second element is configured in the form of a sleeve having a hole with a conical section matching the tapered end portion of the first element. The end portion of the sleeve is configured thinwalled and having an outer diameter greater than the outer diameter of the remaining portion of the sleeve. The locking sleeve is mounted with the head of the first element in a screw bolt mounting hole and fixed in the module by deformation of the thinwalled end portion of the second element located in the hole of the module. The screw bolt can be fixed directly in the module or connected to it by a plug nut having an outer conical surface mating with a cone sleeve forming a threaded connection with the module.
The known device for securing the blanket module to the vacuum vessel of the fusion reactor has a disadvantage that additional machining of the flexible support is required along its length to compensate angular and shear displacements arising from manufacturing errors of the vacuum vessel during assembling process of the module. Additional machining is carried out during the installation process and should be accompanied by constant measurements of the flexible support significantly extending and complicating the mounting operations.
The closest analog to the claimed invention as to the essential features is a device for securing a blanket module to the vacuum vessel of the fusion reactor comprising flexible support in a form of rods located between two flanges, and a displacement compensator mounted by threaded joint on the flange of the support oriented towards the module, said displacement compensator is comprised of a locking screw and supporting sleeve, which are pivotally interconnected, and a coupling sleeve with a spherical protuberance (convex surface), the coupling sleeve connecting the flexible support with the blanket module via a threaded fastener (Russian Patent No. 2491663, IPC G21Bl/13, published on Aug. 27, 2013).
In the indicated device the rods of the flexible support are mounted around the periphery of the flanges forming a cavity in the central part of the flexible support. The threaded fastener is configured in a form of a screw bolt having a head located in the cavity of the flexible support and a rod part passing through the openings in the elements of the displacement compensator and engaging the module with a thread. A flange of the support oriented towards the module is threadably connected to the locking screw of the displacement compensator. The locking screw is configured to have a convex spherical surface, and the supporting sleeve has a complementary concave spherical surface. The coupling sleeve is located to provide a contact with the surfaces of the module and the surfaces of the supporting sleeve, the supporting sleeve is coupled by the spherical protuberance with a cone-shaped recess in the mounting hole of the module. A ball washer is provided between the bolt head and the flange of the flexible support oriented towards the module, wherein the inner surface of the bolt head interfaced with the washer is configured to have a complimentary spherical shape.
Installation of the known device is carried out as follows.
The screw bolt and the ball washer are inserted into the hollow flexible support, the support is then positioned in the mounting socket of the vacuum chamber. A locking screw having a convex spherical outer surface is threadably mounted on the flange of the flexible support oriented towards the blanket module in such a way that the bolt rod extends beyond the flexible support. A supporting sleeve with a concave spherical inner surface is mounted on the locking screw with a convex spherical outer surface. A coupling sleeve with a spherical protuberance is mounted on the threaded end of the screw bolt to align the end faces of the coupling sleeve and the supporting sleeve. The blanket module is positioned on the assembled device in such a way that the conical recess of the module abuts the spherical protuberance of the coupling sleeve.
The known device ensures compensation of the angular and shear displacements arising during the mounting process. In case of a shear (lateral) displacement the coupling sleeve moves over a displacement value thus accommodating possible lateral displacement. In case of an angular displacement, the screw bolt, the supporting sleeve and the coupling sleeve rotate by the value of such angular displacement, thus accommodating the angular displacement, and the axis of the screw bolt is aligned with the axis of the mounting hole.
The bolt is then screwed in using a special tool installed into the mounting hole in the rod portion of the bolt, and the ball washer is automatically installed due to engagement with the spherical surface of the bolt head.
The known device for securing the blanket module to the vacuum vessel of the fusion reactor as described above has a disadvantage that the threaded connection between the bolt and the blanket module is weakened in the process of cycle operation of the fusion reactor. This can be accounted for by the absence of stop elements which cannot be used due to hindered access to the threaded connection caused by spatial restrictions in its location. In addition, another disadvantage of the known device can be defined as the limitation of the permitted torque value for the threaded connection of the flexible support and blanket module due to small cross-section area of the rod portion of the bolt caused by the inner mounting hole.